A sensor switch is a switch that uses a conductive member in an interior thereof to sense vibration so as to open or close a circuit. Because of its sensitivity and ability to detect vibration in all directions, the sensor switch has a very wide range of applications, and is an indispensable electronic component of many electronic products.
Currently, the conductive member of the sensor switch is confined in a cavity defined by a non-conductive shell and two electrodes. The connection between the non-conductive shell and the electrodes is strengthened through an embedding engagement.
One instance of such an embedding engagement is disclosed in FIG. 1 of Japanese Publication No. 2003-161653, wherein two electrode parts (A1, A2) are inserted into a cylindrical body (B) in two opposite mounting directions (10A, 10B), and a cylindrical enlarged head portion 3 of each electrode part (A1, A2) is engaged between annular projections 7, 8, 9 of the cylindrical body (B). However, in order to permit easy assembly of the electrode parts (A1, A2) with the cylindrical body (B), the ratio of the height of each of the annular projections 7, 8, 9 to the diameter of the cylindrical enlarged head portion 3 is too small, so that the electrode parts (A1, A2) cannot be firmly connected to the cylindrical body (B).
Another instance of the embedding engagement is disclosed in U.S. Pat. No. 7,421,793 B2. In this disclosure, two end caps are frictionally fitted into a central member. However, the distal portion of each of the end caps must have a certain length, and the interference fit of the distal portions of the end caps with the central member must be considered at the same time to produce a suitable friction force. As such, not only is the complexity of the manufacturing process of the components increased, the cost associated therewith is also increased. Further, because the connection of the end caps with the central member may be too tight, air pressure generated during assembly thereof may push the end caps outward, so that the end caps may be unstably connected to the central member, even to the point of loosening therefrom.